While the health benefits of breastfeeding are clear, evidence that the practice improves a child's thinking skills is more mixed. A comprehensive 2007 review, for example, found that the cognitive effects of breastfeeding are small and short-lived. But a new study suggests it does bolster brain development for at least one subset of children.
South Korean researcher Kanghyock Koh examined the impact of maternal breastfeeding on the mental acuity of 11,544 children born in the United Kingdom in 2000–01. Using data from British Ability Scale tests, he found the positive effect of breastfeeding was two to two-and-a-half times greater for kids with the lowest test scores, compared to those with the highest. What's more, he reports in the journal Social Science and Medicine, its impact was larger for those who were breastfed longer. In other words, breastfeeding may not make bright kids brighter, but it apparently does benefit the kids who could most use a boost.